Manufacture of nitrogen-containing compounds



Patented Aug. 16. 1949 1 .mwiicmmbe NITROGEN-CONTAIN- p INGC'OMPOUNDS 7 Gerard Dunstan, Buckley and Neif Hunter Ray,

Northwich, England, Ghemica Industries Limited, a eorporati'on of GreatBritain,

assignors to Imperial no Drawing; Amflieation June 25, 1947, Serial I ---.No. 757,060. in Great Britain July 31, 1946 This invention reratesvtothe manufacturelofi comicrrsation. products. from carbon monoxide and aromatic amines; I

We hazve foundthat atenfliciently-higir pressures in the region ot a few thousand: atmosiphones; and at el evaitedtemneratures, carbon monoxid'e'andi primary: aromaticamines can: :be caused to react. giving: condensation products; in: which aromatic amine radicals are: linked through nuclear canbonzatom's by such groups as -CHQH- and I Y According to. the-present invention we. manufacture condensation products, of. amines=- and carbonmonoxide. by. a process which. comprises subjecting a primary. aromatic amine. having, at least. twoof the nositionsv ortho. and ,para. to the amino,.-gro11ps tree. from snbstituenta, and car-- bon. monoxideht'o a. temperature above 150 CI andpreferahly betWeenQUDPand 300 and a pressure. exceeding, I000. atmospheres and; preferably between 2080 and 4000 atmospheres, in the presence of a mineral anitl catalyst.

- Iihe aromatic aminesused-imthisinventioniinelude. aniline, .o-toluidina.p-tolhidine mephenyle ene; diamine...n phenyleneidianrine; benzidine,-. p-- I clriloroaniline,v p.-bnomoani1ine,,. anthranilic. ester (ethyl anthrani-late) mp diaminodi'phenyllmethane. Iidesired, partcr. all .01 theamine may be replaced by. its; Nrformyl derivative. vMixed products/may. also. he obtained. by using two. or more. aminesin the reaction mixture.

The/mineral. acid catalysts. usedin. this ins/ten, tion. include principally nitric,. phosphoric,, hy.+ drochioriic, hydroflfuoricand sulphuric acids, and

salts of such acids with the primary aromatic amine which is used in. the reaction. An example of such a salt is aniline hydrochloride. The amountoficat'awsttu-sediis between 0.x]: and bywei'ghtfzofthe amine-iandfi is generallyrbetween 032 and'1'.% preferably-015%. I

- In; one=manner of-carryingr outithis invention the primary aromatieamine=is= put lintmaiprese sure vessel along-'with a-isuitahle-"amountzofimine erahacidicata'lyst. Ittis desirabletocuseaspires sure vesseli-which: ii madedoff'or lined; wit'ha a; corrosion-resistantmaterial. in order to avoid contamination of the products. The pressure vessel is-' then closedandcarbon-monoxide-is injected underpressure, and the: vessel is heated to thedesired temperature; Thereaction then commences and *the pressure fans-"due to the re-'- action, or may be maintained if preferred by in jection ofmore carbon monoxide. Itissdesirable 'to agitatethe reaction mixture =in1ord erthat the reaction shalhproceefiat a satisfactory rateaan'd in order to produce more homogeneous products. The reaction may be'aliowed to proceed untiP-nci further drop'inpressure' occurs. orit maybeim terrupted at an earlierstage if desired; Thev'es set is allowed to 0001*, the pressure" is released and the vessel is open-ed. The reaction mixture-thus; obtained may be a viscous liquid or a -s'o1 id ,"d'e"-" pending on the conditions chosen, and maybe a: pure condensation product bu't is generally a mixture of condensationproducts containing'difi rerent numbers" amine radicals joined by +crn+ or CHQHL- groups. If desiieui nre products can be. separated from this mixturety fractional distillation or by fractional? dissolution except in the case of insoluble and ififu's'lfife? products 'lthereactionmayal'so be carried out as tinnonsv process in which the. reactants are fat? or injected; continuously into a. reaction vessefo'ii' series oi vessels maintained. at a snitabl'eptem perature. andpmssure and the products. are. removed-therefrom.. In certain-cases it is 'conveni ent torcar-ry out the reaction in presence of a liquid. medium such as water orbenzene; but generally-i this is undesirable. because. it is-theii; necessary ftfi separate the: products from the liquid medium.

. "The time .r equiredzfor thezreactions depends-en theamine used the conditions and methodoI- 'op 'eration and the.- type of product desired; but is generatly between l and 24 hours- Attempera' tures of between-? and 200 C. the reaction is slow and: therefore the time: required-is i enerally between. 15-andw 2 i=- hoursh Above 30-0 C.- there action is: much more rapid; but care must be taken to" avoid decomposition ofthe mactants andltherproductsa Forthesemreasons;we=preferto use tem-pera-tures between 200 and-300 G.

Although we do not to'be limited by this explanation, we: believe thatthe reaction pro .ceeds-..by way of. thecarbon monoxidehnking with th.e-,-N-I-Iz1group'o-the primary aromatic amine tcrgiePan 'N-iorrnyl derivativee and; we believe: that. this, derivative then reactsiwithaone or more further-rmolecules-oi amine and-undergoes molecular: rearrangemesnti sea as' tan-produce a: molecule :.in= which two or more lBi-flififilSF are" linked-by- -ai--CHGI-I-- .group through the=carbon atomsrimthe ortho or paira position to the-amine group. Thus the. amine -requires :twoasuch pestp .tions freerfrom substituents in order to build'up anmolecuiar chain containing-three ormore aromaticxamine residuesi Increasei-n'thevtem peratures at which the reaction is carried outsaisists this reaction. We have shown that by raising the reaction temperature the products obtained are of increased molecular weight. Thus an NH2 group of the diamine produced by linkage of two primary aromatic amine molecules reacts with further carbon monoxide in the same manner to give an N-formyl derivative, and

then reacts with a further amine molecule and undergoes molecular rearrangement. In this way a polymeric amine is built up containing two or more units of the original amine per molecule and generally containing between 3 and 6 molecules of the original amine per molecule. The size of the polymeric amine molecule depends inter alia on the original amine and on the reaction temperature. occurs at a high pressure, and the effect of increasing pressure assists this reaction and also assists in a further reaction in which the.

-CHOH linkage is reduced to a CH2- linkage. Thus we can vary both the size ofthe polymeric amine molecule and also the proportion of .-CHOH- and CH2 linkages in these molecules. To some extent long reaction times have the same effect as increased temperature and pressure, i. e. diamines and triamines can be produced with short reaction times of the order of 1 hour, and higher amines such as hexamines and decamines can be produced with reaction times of the order of 24 hours.

In this way, the temperature, pressure and time of reaction are all independent variables which may be chosen according to the product desired. At the lower temperatures and pressures within the preferred ranges th products are viscous liquids containing free amino groups. At; the higher temperatures and pressures in the preferred ranges, the product is a hard solid of high melting point containing a large number of molecules of the original amine per molecule and in which th primary amino groups have been mostly converted to formyl amino groups. This solid is insoluble in dilute aqueous acids and decomposes on heating before its melting point is reached. Thus we may obtain products ranging from viscous liquids through soluble and fusible solids to insoluble and infusible solids depending upon the complexity of the original amine and on the reaction conditions chosen. The product obtained is generally a mixture which can be separated into fractions by successively extracting the soluble portion with mineral acid solutions of appropriate concentration. The lower molecular weight fractions are dissolved by the more concentrated acid, and vice versa, The final residue, which is not dissolved by the most dilute acid, is the high molecular weight, insoluble formylaminocontaining product mentioned above, although this fraction is only produced in a high proportion when the reaction is prolonged and only at the upper limits of temperature and pressure. Theacid-soluble fractions may be recovered from their acid solutions by neutralisation with alkali, or they may be obtained as their salts with the acid by concentration of the solution.

The invention is illustrated but not restricted by the following examples in which all parts are by weight. The first example illustrates the formation of a soluble basic resin from aniline, and the second illustrates the formation of an insoluble basic resin from benzidine. Subsequent examples illustrate the use of difierent classes of amines, and the use of different reaction conditions.

The reaction only Example 1 200 parts of aniline and 1 part of concentrated hydrochloric acid of specific gravity 1.16 are put in a stirred stainless steel vessel of capacity approximately double the total liquid volume. The air remaining in the vessel is replaced by carbon monoxide under pressure, and the vessel is heated to 250 C. Additional carbon monoxide is then added until the total pressure is 3000 atmospheres.- The reaction proceeds, and more carbon monoxide is added to maintain the pressure at 3000 atmospheres. After 15 hours the vessel is cooled and the pressure is released. The product obtained is 250 parts of a brown solid, of which is soluble in N/10 hydrochloric acid, and has a molecular weight of 400.

Example 2 200 parts of benzidine and 1 part of concentrated hydrochloric acid of specific gravity 1.16 are put in a stirred stainless steel vessel with carbon monoxide as in Example 1. The temperature and pressure are raised to 250 C. and 3000. atmospheres respectively, and during 24 hours the temperature is kept at 250 C. and the pressure falls gradually to 2500 atmospheres. The product is 220 parts of a hard, infusible, insoluble resin which can be used as an anion exchange resin. Example 3 40 parts of m-phenylene diamine and 0.1 part of concentrated hydrochloric acid of specific gravity 1.16 are put in a stirred steel vessel with carbon monoxide as in Example 1. The temperature is raised to and maintained at 200 C., while the pressure which is raised initially to 3000 atmospheres falls during 20 hours to 2500 atmospheres. The product is 41 parts of a brown solid which is soluble in dilute acids, melts at 60-120 C., and has a molecular weight of 600.

Example 4 40 parts of ethyl anthranilate and 0.1 part of concentrated hydrochloric acid of specific gravity 1.16 are put in a vessel with carbon monoxide as described in Example 1. The temperature is raised to and kept at 250 C., and the initial pressure is 3000 atmospheres. After 20 hours the pressure has fallen to 2100 atmospheres and on cooling the vessel and releasing the pressure the product obtained is 40 parts of a solid which is soluble in dilute acids. This product contains ester groups which are hydrolysable to give an amphoteric compound soluble in water, acids and alkalies.

Example 5 40 parts of p-bromoaniline and 0.1 part of concentrated hydrochloric acid of specific gravity 1.16 are reacted with carbon monoxide as described in Example 1, the temperature and pressure being kept throughout at 250 C. and 2500 atmospheres respectively. After 24 hours the product obtained is 42 parts of a light brown solid which is soluble in dilute hydrochloric acid.

Example 6 20 parts of formanilide, 30 parts of aniline and 2 parts of aniline hydrochloride are treated with carbon monoxide as described in Example 1. The temperature is raised to and maintained at 250 C. and the pressure is raised to 2000 atmospheres and is maintained constant by periodic additions of more carbon monoxide. After 20 hours there is obtained 50 parts of a viscous liquid containing parts of unchanged aniline which are separated by distillation, leaving a very viscous liquid. From this liquid two products can be obtained by continued distillation; one is 10 parts of a low molecular Weight fraction boiling from 160230 C., and the other is parts of a pitch-like residue which is soluble in dilute acids.

Th products which are soluble in dilute acids may be used as intermediates in the manufacture of dyestuffs and synthetic resins. The products which are insoluble, in particular those derived from aromatic diamines such as benzidine, may be used as anion exchange resins. Some of the products obtained by this reaction are themselves novel products. In particular, those containing three or more molecules of aromatic amine per molecule of product and linked through CHOH-- groups are new products which have not hitherto been obtained and may be represented by the general formula NH: NH: NH: rz-onon-iv-onorhlt" where R, R. and R. are the same or different aromatic groupings. For example, the higher amines containing 4 or more amine molecules per molecule of condensation product are products which have this general formula in which R and R are the aromatic residue of the original aromatic amine, and RNH2 is a diamine or polyamine produced by condensation of two or more of the original amine molecules with carbon monoxide. If desired, part or all of the CHOH- groups may be replaced by --CH2- groups as stated hereinbefore.

What we claim is:

1. A process for obtaining condensation products which comprises heating carbon monoxide and an amino compound in contact with a catalyst under a pressure above 1000 atmospheres at a temperature of from C. to 300 C., said amino compound being selected from the group consisting of primary aromatic amines having at least two of the positions ortho and para to the amino roup unsubstituted and N-formyl derivatives of said amines, said catalyst being selected from the group consisting of mineral acids and salts of said acids with said amines.

2. A process for obtaining condensation products which comprises heating carbon monoxide and an amino compound in contact with a catalyst under a pressure of 2000 to 4000 atmospheres at a temperature of from 200 C. to 300 C., said amino compound being selected from the group consisting of primary aromatic amines having at least two of the positions ortho and para to the amino group unsubstituted and N-formyl derivatives of said amines, said catalyst being selected from the group consisting of mineral acids and salts of said acids with said amines.

3. A polyamine condensation product of carbon monoxide and an aromatic compound in contact with a catalyst under a pressure above 1000 atmospheres at a temperature of from 150 C. to 300 C., said amino compound being selected from the roup consisting of primary aromatic amines having at least two of the positions ortho and para to the amino group unsubstituted and N-formyl derivatives of said amines, said catalyst being selected from the group consisting of mineral acids and salts of said acids with said amines.

GERARD DUNSTAN BUCKLEY. NEIL HUNTER RAY.

REFERENCES orrEn The following references are of record in the file of this patent:

Liston et al., Ind. Eng. Chem.," 26, 1073-1074 (1934). 

